- Start the FME Workbench. Create a blank workspace.
- Select Readers | Add Reader. In the Format field, choose ASPRS Lidar Data Exchance Format (LAS). Choose a dataset e.g. C:\data\lub_tile1.las. Click OK.
- Select Writers | Add Writer. In the Format field, choose Comma Separated Value (CSV). Choose an output dataset e.g. C:\Temp\.
- Click Parameters. If necessary, change the extension from the default csv. Choose another Separator Character if comma is not wanted. Click OK.
- Click OK again.
The prompt appears.
- Click Yes.
The Feature Type Properties dialog box appears.
- In the Feature Type Name field, type in the output CSV file name e.g. outascii.
- Click the User Attributes tab. Define number attributes for the X,Y,Z values as shown below. Click OK.
- From the Transformer Gallery, drag and drop the PointCloudCoercer, CoordinateExtractor, and Tester transformers onto the workspace.
- Connect up the source, transformers and destination as shown below.
- Open the PointCloudCoercer Parameters. Change the Output Geometry to Point. Click the Point Components to Preserve button and select all. Click OK.
- Open the Tester Parameters. Define a Test Clause as shown below to allow only ground points (class=2). Click OK.
- Run the translation.
The output ASCII CSV file is created.
Monday, August 22, 2011
Export ground points from a LAS file to ASCII CSV file using FME
This is one of the typical LiDAR file conversion task - converting a LAS (*.las) file to an ASCII XYZ or CSV (*.csv) file. It can be done with any number of free and commercial software. It is a simple matter to define a workspace using the FME Workbench from SAFE to do the job. Here are the steps that I used to export out only ground points from a LAS file into an output ASCII CSV file.